Cyst on remaining portion of pancreas after surgery

I had successful surgery for pancreatic cancer on Sept 9, when half the pancreas and all of the spleen was removed. However continued to have sever pain for the next three months. Finally they found that I have developed a cyst on the remaining portion of the pancreas, put me on time-released pain medication and took a "lets-wait-and see-what happens" attitude. SO...5 months after surgery I am either in extreme pain or "half-drunk" from the pain meds! I am scheduled for another CAT scan the first of March to see if they cyst has shrunk or grown, but I can not help but feel that it is still very much there or else why the pain? I also worry about becoming addicted to the pain medication (codeine). They did tell me that if it has grown or has not shrunk it would mean more surgery because there is so much scar tissue and not much pancreas left. It is terribly hard not to be depressed, wondering if maybe they are wrong and it IS cancer again, wondering if the cyst will come back if they do have to do surgery, wondering if I will EVER be my old self again. Has anyone else had this develope? If so, what was the outcome? Did the cyst return after being drained?